That said, you do end up with something approximating a state of equilibrium. Most governments cannot go too far right or left because they become unelectable. The exception within living memory is of course Margaret Thatcher's conservatives in the 80s, where their electoral popularity was dependent principally on the outcome of the Falklands war.
Well, you end up with what we've got. Both Labour and Conservative pandering to their extreme supporters as much as they can whilst maintaining the possibility of them achieving a majority. As others have pointed out, neither May nor Corbyn were that far away from a majority.